1gruH:23-525 1xckF:23-525 1kp8E:23-525 1pcqJ:23-524 1aonJ:23-524 1mnfI:23-525 1svtJ:23-524 2c7dK:23-525 1dkdC:190-335 1j4zL:23-525 1oelE:23-524 2c7cH:23-525 1gr5H:23-525 1sx4E:23-524 1kid :190-375 1gr6F:23-525 1ss8B:23-524 1fy9A:190-375 1dk7A:190-335 1jon :190-335 1la1A:187-378 1iokA:23-526 1wf4e:22-526 1we3E:22-526 1sjpB:42-522 1srvA:1-143 1a6dB:33-521 1a6eB:33-521 1e0rB:215-366 1ass :214-364 HSP60, also known as chaperonins (Cpn), is a family of heat shock proteins originally sorted by their 60kDa molecular mass.

HSP60 belong to a large class of molecules that assist protein folding, called molecular chaperones.

[2][3] Newly made proteins usually must fold from a linear chain of amino acids into a three-dimensional tertiary structure.

Methanococcus maripaludis chaperonin (Mm cpn) is composed of sixteen identical subunits (eight per ring).

They instead contain a "built-in" lid that closes in an ATP-dependent manner to encapsulate its substrates, a process that is required for optimal protein folding activity.

[14] Chaperonins undergo large conformational changes during a folding reaction as a function of the enzymatic hydrolysis of ATP as well as binding of substrate proteins and cochaperonins, such as GroES.

According to recent analyses by different experimental techniques, GroEL-bound substrate proteins populate an ensemble of compact and locally expanded states that lack stable tertiary interactions.

These protein complexes appear to be essential for life in E. coli, Saccharomyces cerevisiae and higher eukaryotes.

[21] Like GroES, gp31 forms a stable complex with GroEL chaperonin that is absolutely necessary for the folding and assembly in vivo of the bacteriophage T4 major capsid protein gp23.

[22] Human GroEL is the immunodominant antigen of patients with Legionnaire's disease,[10] and is thought to play a role in the protection of the Legionella bacteria from oxygen radicals within macrophages.

This hypothesis is based on the finding that the cpn60 gene is upregulated in response to hydrogen peroxide, a source of oxygen radicals.